Mixer-grinder for foundry sand



Dec. 12, 1967 R, A. M. RoNcx-:RAY

MIXER-GRINDER FCR FOUNDRY SAND 2 Sheets-Sheet 1 Filed Jan. 29, 1965 SNNQ Dec. l2, 1967 R. A. M. RONCERAY Y 3,357,648

MIXER-GRINDER FOR FOUNDRY SAND 2 Sheets-Sheet 2 Filed Jan. 29, 1965United States Patent O 3,357,648 MIXER-@KINDER FOR FOUNDRY SAND RobertAndr Marcel Ronceray, 122 Ave. des Champs Elysees, Paris 8, France; LenaSarah Yeomans, Andree Jacqueline Laure Ronceray, Franoise Monique MaryRonceray, and Pierre Robert Roncel'ay, heirs of said Robert A. M.Ronceray, deceased Filed Jan. 29, 1965, Ser. No. 429,045 Claimspriority, application France, Feb. 14, 1964, 963,8l9 4 Claims. (Cl.241-110) ABSTRACT F THE DISCLOSURE A mixer-grinder has a pan ofrelatively substantial depth mounted to rotate about a central shaftwhich is stationarily mounted on a frame. A unit is stationarily mountedon the upper extremity of the shaft and the unit has a feed hopper forsupplying material to the pan close to the center thereof. One or moreaxles are stationarily mounted on the unit above the pan and a muller ofovoid longitudinal cross section is mounted to rotate freely on eachaxle. An arm is stationarily mounted on the unit parallel to itsassociated axle and each arm supports a plurality of discs which can beseparately oriented.

The present invention has for its object a mixer-grinder for foundrysand, that is to say a device which is intended to effect the intimatemixture of the sand with the different addition products which areusually contained in foundry sand. The mixture thus obtained will bereferred to hereinafter as sand. rPhe operation which the said device isintended to'perform not only entails a simple mixing process but alsothe grinding of the particles which form the nal mixture.

It has already been proposed to construct devicesy of this type whichcomprise a rotatably driven tray for receiving the sand to be processed;there being placed within said tray mullers for crushing the sand andbreaking up the lumps which may be present: provision is also made forat least one and preferably two series of discs which are mounted onapproximately radial arms and the intended function of which is tofacilitate the mixing of the constituent materials.

However, the devices of this type which havealready been produced areattended by certain disadvantages which it is precisely the aim of thisinvention to circumvent.

In particular, the above-mentioned tray has been designed up to thepresent time in the form of a relatively shallow casting which is drivenin rotation as a result of the cooperation of a toothed ring rigidlyfixed to said tray with a pinion which is mounted on a driving shaft.This arrangement entails the need to machine the tray which cannot beemployed in the as-cast state and it is observed that, in spite of thisprecaution, the device generates a high level of noise and producespowerful vibrations which result in premature wear.

The present invention has for its object a device of this type in whichthe sand circulates continuously, that is to say in which the supply ofsand to be processed as well as the discharge of processed sand takesplace in a continuous manner.

The device in accordance with the invention comprises in combination apan of relatively substantial depth in which are mounted the grindingand mixing devices, a feedhopper which is intended to be continuouslysupplied with sand which is conveyed by said hopper in the vicinity ofthe center of the pan, at least one ovoid muller which is mountedparallel to the radius of the pan, and at least ICC one peripheraloutlet which permits the discharge of processed sand and which isassociated with a deflector device for bringing the peripheral layer ofsand into said discharge outlet.

In accordance with one characteristic feature of said device, the pan issupported at the center by a stationary shaft and carried on at leasttwo wheels tted with tires on which said pan rests, at least one of saidwheels being mounted on an axle which is driven positively in rotation.

ln an advantageous form of embodiment of the invention, the rotary axlereferred to is the output shaft of a motor and more advantageously of areduction gear motor, with the result that the tire is directly drivenin rotation.

In another advantageous form of embodiment of this invention, the ovoidmuller is mounted to rotate freely on an axle which is substantiallyparallel to the radius of the pan but which is displaced to the rear ofsaid radius relatively to the direction of rotation of the said pan.

Vertical discs are mounted in front of each of the mullers which arepreferably two in number and on a supporting arm parallel to the armwhich carries the muller, the plane of said vertical discs making avariable angle with the shaft on which said discs are mounted.

It will be noted in particular that the device in accordance with theinvention is not provided with any stationary scraper, such scrapersbeing replaced by the above-mentioned discs which are capable of motion;the result achieved by this arrangement is that wear is distributed overa greater length (external diameter of the discs), which accordinglyreduces the rate of wear, requires less Vfrequent adjustments and, inaddition, achieves more effective mixing of the sand as a result of amore powerful stirring action.

In a particular form of execution of the assembly of the aforesaiddiscs, each disc referred to is mounted elastically with respect to theshaft which supports the combined assembly of discs of one series, insuch a manner that the discs are lifted when a hard foreign body passesaccidentally into the apparatus; this arrangement prevents thedestruction of the discs.

The angle which is made by the line at right angles to the plane of thediscs with the axis of the shaft which carries said discs is such thatthe sand is brought back towards the mean radius of the pan; since theresultant action of the ovoid profile of the mullers, the portion ofkgreatest thickness of which is located precisely in said means radius,is exerted in the opposite direction, there are thus obtained twoactions which oppose each other to a certain extent.

It is thus possible to modify the angle of inclination of each disc inorder that the centrifugal motion has a slight preponderance which issufcient to ensure that the mixture of sand is homogeneous and aeratedwhen said mixture reaches the periphery of the pan so as to bedischarged.

Further characteristic features of the invention will be brought out bythe following description, reference being made to the accompanyingdrawings which are given by way of example without implied limitation,and in which:

FIG. 1 is a view in elevation and in substantially diametrialcross-section of an apparatus in accordance with the invention;

FIG. 2 is an overhead plan view;

FIG. 3 is a detail view which illustrates the assembly of the discs onthe shaft which supports these latter.

The apparatus in accordance with the invention is mounted on a frame 1which is of circular configuration, for example, to which is secured acentral vertical shaft 2 for the purpose of supporting and centering thepan 3.

As will be apparent especially from FIG. 1, the said pan is ofrelatively substantial depth and rests on wheels such as the wheel 4,each wheel being fitted with a tire 5, 5a which is inflated with air ata pressure which is determined by experiment.

The half-axles such as 6 on which the above-mentioned wheels are mountedare each carried on a plate 7 which has in cross-section the shape of aT with unequal arms. The longest arm or upper arm of the T receives thecorresponding half-axle and the lower arm 8 rests on the frame 1 towhich the central perpendicular arm 9 is fixed in any suitable manner,for example by means of a bolt or screw 10.

An individual reduction gear motor such as the motor 11 and the motor 12is mounted on the half-axle 6 of at least one and preferably two wheelstted with tires, with the result that the said wheels communicate themovement of rotation of the axle to the pan 3; this arrangement has alarge number of advantages and in particular the following: by virtue ofthe presence of the tire combined with the weight of the pan 3 and itscontents, the driving of the pan in rotation is carried out withoutslippage and, in addition, this driving motion is essentially noiseless.Furthermore, the tires permit the possibility of employing an as-castpan since they absorb any roughness of the outer surface of said pan, sothat the driving motion is performed noiselessly and without vibrations.

The pan 3 is mounted on the shaft 2 through the intermediary of thesleeve 13 and nut 14 between which is interposed a tapered rollerbearing, thereby avoiding any appreciable tilting of the pan if one ofthe tires were to become deflated. It is additionally observed that thesaid tapered roller bearing is perfectly unobstructed and very easy ofaccess from the exterior, with the result that the positional adjustmentof the pan relatively to the shaft 2 is greatly facilitated.

As will be understood, it is within the scope of this invention toprovide a number of wheels which is sufficient for the purpose ofensuring perfect balancing of the pan. For example, provision can bemade for three wheels which are spaced at an angle of 120 from eachother. However, as will also be understood, it is not essential that allof the wheels thus provided should be driving wheels. On the contrary, acertain number of such wheels can be mounted to rotate freely in such amanner as to perform solely a supporting and guiding function.

There are mounted in the interior of the pan 3 two mullers 15 and 16which are distinguished by their ovoid shape and the maximum diameter ofwhich, located at approximately one half the length thereof as shown at17 in the case of the muller 16, is located virtually at the level ofthe mean radius of the pan 3. The ovoid shape of said mullers makes itpossible to set these mullers at a distance from the pan which can bemade to decrease according to any given law and in as progressive amanner as may be desired. The result thereby achieved is that there isobtained in a simple manner an increasing compression of the sand as thesand is displaced towards the periphery of the pan.

The axle such as 18 on which the muller 16 is mounted is substantiallyparallel to the radius 19 of the pan but is displaced to the rear asshown in FIG. 2 in the case of the axis 20 relatively to the directionof movement of the pan which is indicated by the arrow F. The result ofthis arrangement is to permit a radial sliding movement of the sandbeneath the mullers and a better attack of the sand which, as has beenobserved from experiment, passes beneath the mullers without drifting infront of these latter.

The half-axles which support the mullers 15, 16 are mounted on a kind ofyoke 21 which, as shown more especially in FIG. l, is :mounted astridethe sleeve 13 around the exterior of this latter and carried on rollerbearings which are fitted in the interior of said sleeve 13 and at leastone of which is a tapered roller bearing.

The two half-shafts 22, 23 which carry the discs 24, 25,.

26, 27 and 28 are also mounted on the ends of the yoke 21 on each sideof the vertical shaft 2. The discs referred-to are freely mounted in themanner which will be indicated below and are intended to work and aeratethe sand while at the same time distributing the sand in a suitablemanner in front of the muller.

The line at right angles to the plane of each disc makes an angle a withthe axis of the shaft 22 which is variable according to the discconsidered.

By way of example without any limitation of the invention being therebyimplied, the angle a relative to the disc 24 can be chosen equal toapproximately 43; the angle a relative to the disc 25 can be equal toapproxi- -mately 33; the angle a relative to the disc 26 can be equal toapproximately 27, and so forth in sequence up to the angle made by thedisc 28, which can be of the order of 5.

The discs which are mounted on the shaft 23 make an angle a which is ofsubstantially the same order, the discs which are symmetrical withrespect to the shaft 2 having substantially the same angle of slope.However, it will be noted that provision is made for an additional disc29 to which there corresponds an angle a of the order of 13, but theslope of which is in a direction opposite to that of the other discs, ascan clearly 4be seen from FIG. 2. The intended purpose of said disc 29is to bring back the sand located at the periphery towards thecorresponding muller 15.

Similarly, provision is made for a disc 30 which is associated with theshaft 22 so that the line -at right angles to the axis of symmetry ofsaid disc makes an angle of approximately 13 with the axis of saidshaft, said disc being placed in such a manner as to direct the Sandtowards the discharge chute 31. 'To lthis end, said disc 30 isorientably mounted on a shaft 32 which is in turn carried by an arm 33,said arm being pivoted on the shaft 22.

It will be understood that, depending on the nature of the sand, it willbe possible to modify the angle made by each disc with the axis of theshaft on which said disc is carried.

FIG. 3 shows the manner in which the discs are supported by a shaft suchas the shaft 22.

There is rst of all provided a ring 34 which is keyed on the shaft 22,for example by means of the screw 35; said ring is associated with aring 36 which is loosely mounted on this same shaft, the two rings 34,36 referred to being connected by means of a spring 37, one end 38 ofwhich is fitted within a blind-end bore of the loose ring 36; the otherend of the spring is designed to penetrate into a recess 39 of theadjacent `loose ring 42 after lhaving been passed through an opening ofthe fixed ring 34; a screw 41| which is screwed into said adjacent loosering 42 is brought to bear -against the corresponding extremity 41 ofthe spring which is located within the recess 39. The extremity 41 ofthe spring therefore serves as a fixed bearing point for said spring andat the same time serves as a bearing member about which theabovementioned loose ring 42 can be oriented.

The discs are mounted on vertical rods, this assembly being carried outin -a known manner, the said rods being each inserted in an opening suchas the split collar 43 which is formed in each of the loose rings. It istherefore possible to vary the orientation of the plane of the discrelatively to the shaft 22 by slackening off the nut 44 which is mountedon the bolt 45.

Should a hard object fall accidentally into the pan and reach the levelof the discs, the disc or discs encountered by such an object can belifted by causing the loose ring 36 to rotate -in opposition to thespring 37; the hard object wil-l thus pass Without causing damagebeneath the line of discs, the disc or discs thus lifted being thenreturned to the initial position as a result of the action of the springor springs.

The adjustment of the screw 40 which is applied against the fixedextremity of the spring permits the possibility of adjusting the initialangular keying of the loose ring with respect to the shaft 22. Finally,the length of the recess 39 is a measure of the possible displacement ofthe disc in the vertical direction. Thus, referring to the discconnected to ring 42, if this disc is displaced upward-ly, the ring 42will rotate about the axis of shaft 22 until the lower end wall ofrecess 39 abuts against the extremity 41 of the spring 37 to limitfurther rotation of said ring and thereby prevent further upwarddisplacement of the disc mounted on said ring.

The sand to be processed is continuously fed in through the hopper 46,that is to say near the center of the pan 3 and is subjected to theaction of the mullers and of the discs. The sand is then dischargedthrough the discharge chute 31 by means of the disc 30.

What is claimed is:

1. Mixer-grinder for foundry sand comprising in combination a centralshaft stationarily mounted on a frame, a pan of relatively substantialdepth which is mounted to rotate yfreely on said shaft, 'a radial unitstationarily mounted at the upper extremity of said shaft, a feedhoppercentrally carried by said unit and provided with a conduit which has itsopening close to the center of the pan, two half-axles stationarilymounted on said unit 4and extending in opposite directions from saidunit at right angles thereto, a muller of ovoid longitudinal-cross-section mounted to rotate freely on each of said half-axles, twoarms stationarily mounted on said unit and each arm being parallel tothe half-axle which is located on the same side of the stationary unitas said arm, discs mounted on each of said arms in separately orientablemanner, a discharge chute located at the periphery of said pan, adecctor orientably mounted at the extremity of that arm which isadjacent said discharge chute, and means for rotating said pan.

2. Mixer-grinder for foundry sand comprising in combination a centralshaft stationarily mounted on a frame, a pan of relatively substantialdepth which is mounted to rotate freely on said shaft, a radial unitstationarily mounted on the upper extremity of said shaft, a feedhoppercentrally carried `by said unit and provided with a conduit which opensnear the center of the pan, two half-axles stationarily mounted on saidunit and extending in opposite directions from said unit at right anglesthereto, a muller of ovoid longitudinal cross-section mounted to rotatefreely on each of said half-axles, two arms stationarily mounted on saidunit and each arm being paraldel to the half-axle which is located onthe same side of the stationary unit as said arm, discs mounted on eachof said arms in separately orientable manner, a discharge chute locatedat the periphery of said pan, a deiiector which is orientably mounted atthe extremity of the arm which is located near said discharge chute, atleast two wheels fitted with tires and mounted on the Iframe, areduction gear motor set carried by said frame, at least one of saidwheels being keyed to the output shaft of said reduction gear motor set,and the pan being carried 0n said wheels.

3. Mixer-grinder for foundry sand comprising in combination a centralshaft stationarily mounted on a frame,

a pan of relatively substantial depth which is mounted to rotate freelyon said shaft, a radial unit stationarily mounted at the upper extremityof said shaft, a feedhopper centrally carried by said unit and providedwith a conduit which has its opening close to the center of said pan,two half-axles stationarily mounted on said unit and extending inopposite directions from said unit at right angles thereto, a mullerhaving an ovoid longitudinal cross-section and mounted to rotate freelyon each of said half-axles, two arms stationarily mounted on said unitand each arm being parallel to the half-axle which is located on thesame side of the stationary unit as said arm, a plurality of discs,sleeves supporting the discs, said sleeves being freely mounted on eachof said arms, stationary sleeveskeyed to said arms and separating' saidfreely-mounted sleeves from each other, elastic coupling members forsecuring each freely-mounted sleeve to an adjacent stationary sleeve,and means for rotating said pan.

4. Mixergrinder for foundry sand comprising in combination a framehaving a central vertical shaft, at least three Wheels tted with tiresand spaced at equal angular distances from each other relatively tothecentral vertical shaft carried by said frame, a pan which is guided bysaid shaft and carried on said wheels, means .for rotating at least oneof said Wheels, at least one muller freely mounted on a muller axlewhich is generally parallel to a radius of the pan and displaced to therear of said radius relatively to the direction of rotation of the pan,the peripheral surface of said muller being located at a short distancefrom the bottom of said pan, at least one arm which is substantiallyparallel to said muller axle and located in front of said axlerelatively to the direction of rotation of the pan, a plurality ofdiscs, a disc-carrier rod to which each disc is rigidly fixed and whichis adapted to pass through a sleeve which is freely mounted on said arm,means for adjusting the angular position of said rod with respect tosaid sleeve, means for adjusting the angular position of said sleevewith respect to said arm, said adjusting means comprising an elasticmember which brings back said sleeve into the initial position thereofwhen said sleeve has been displaced therefrom, and a discharge chutewhich has its opening in said pan in the vicinity ofthe peripherythereof.

References Cited UNITED STATES PATENTS 12,054 12/1854 Cutler 241-117952,820 3/ 1910 Lansdowne 241-117 3,304,588 2/1967 McIlvaine 241-110 XFOREIGN PATENTS 344,449 6/ 1904 France. 545,663 10/ 1922 France.1,342,129 6/ 1963 France.

43 8,491 10/ 1925 Germany. 596,517 8/ 1933 Germany 278,069 9/ 1927 GreatBritain. 322,185 10/ 1934 Italy.

WILLIAM W. DYER, JR., Primary Examiner. R. I. ZLOTNIK, AssistantExaminer.

1. MIXER-GRINDER FOR FOUNDRY SAND COMPRISING IN COMBINATION A CENTRALSHAFT STATIONARILY MOUNTED ON A FRAME, A PAN OF RELATIVELY SUBSTANTIALDEPTH WHICH IS MOUNTED TO ROTATE FREELY ON SAID SHAFT, A RADIAL UNITSTATIONARILY MOUNTED AT THE UPPER EXTREMITY OF SAID SHAFT, A FEEDHOPPERCENTRALLY CARRIED BY SAID UNIT AND PROVIDED WITH A CONDUIT WHICH HAS ITSOPENING CLOSE TO THE CENTER OF THE PAN, TWO HALF-AXLES STATIONARILYMOUNTED ON SAID UNIT AND EXTENDING IN OPPOSITE DIRECTIONS FROM SAID UNITAT RIGHT ANGLES THERETO, A MULLER OF OVOID LONGITUDINAL CROSS-SECTIONMOUNTED TO ROTATE FREELY ON EACH OF SAID HALF-AXLES, TWO ARMSSTATIONARILY MOUNTED ON SAID UNIT AND EACH ARM BEING PARALLEL TO THEHALF-AXLE WHICH IS LOCATED ON THE SAME SIDE OF THE STATIONARY UNIT ASSAID ARM, DISCS MOUNTED ON EACH OF SAID ARMS IN SEPARATELY ORIENTABLEMANNER, A DISCHARGE CHUTE LOCATED AT THE PERIPHERY OF SAID PAN, ADEFLECTOR ORIENTABLY MOUNTED AT THE EXTREMITY OF THE ARM WHICH ISADJACENT SAID DISCHARGE CHUTE, AND MEANS FOR ROTATING SAID PAN.